Hydraulic material handling apparatus



Nov. 18,1958 W. R. PETERSON 2,860,908

HYDRAULIC MATERIAL HANDLING APPARATUS Filed April 12, 1956 IIIIII Il IN1/wrox ya Zier @femm By Avon/vm United AStates Patent 2,s60,9os HYDRAULIC MATERIAL HANDLING APPARATUS Walter R. Ieterson, Alexandria,Va., assignor to the United States of America asrepresented by the Sec- `retaryoftheArmy i Application April 12, rsjseriaiNo. 577,899

y 1 Claim. (01.294488) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein :may be manufactured and used byor for the Government for governmental purposes without the paymentof any royalty thereon.

The 'present invention relates to load supporting devices and more particularly to an hydraulic apparatus to be used as an .attachment with-.acrane or`hoist-hook for the precise lowering of a heavy load into a desired location.

It is an object of the instant invention to bring a heavy article suspended by a crane or hoist from a position slightly above the place it is to'occupy down in the exact desiredilocation with great slowness and accuracy.

It is' another object of this linvention to provide an hydraulically operated apparatus to be used in conjunction with a crane or a hoist to deliberately and'accurately lower a heavy load to a desired final location, orto a position in which it can be -easily meshed with or brought into engagement with a stationary object, asin progressively adding heavy parts to a structure.

It is a further object ofthe invention to provide an attachment for cranes or hoists for slowly lowering heavy loads by releasing controlled volumes of enclosed hydraulic fluid from beneathH loadsupporting pistons.

Another object of theinvention is tolprovide'a voonstruction whereby load supporting pistons may be slowly and deliberately lowered by the downward force of the load acting yagainst the resistance of -hydraulic fluid to passage or ow through a restricted aperture of variable magnitude and against the increasing resistance of coiled springs.

Desirable features of an hydraulic material handling and load lowering apparatus are short effective length so that hook elevation for a given crane installation will be decreased a minimum .amount when the apparatus is attached, a load supporting hook that can be independently mounted for easy swiveling without Vthe need for costly machining of parts, and means for slowly releasing enclosed load supporting hydraulic fluid by remote control.

It is, therefore, an object of this invention to minimize the loss of eifective crane height by providing a specially designed auxiliary load lowering apparatus.

Another object is to provide a material handling and load lowering apparatus having a load supporting hook mounted in a frame between two load carrying pistons in a manner to permit ease of swiveling and relatively friction free rotation of the hook independently of its supporting frame.

A still further object of the invention is to provide a construction whereby release of hydraulic iiuid supporting a load carrying piston can be accomplished through the operation of a val've in a location remote from the apparatus. l

Other objects and a more thorough understanding of the invention may be had by reference to the following description and claims taken in conjunction with the accompanying drawings which show an illustrative embodiment ofthe construction forming the basis of the invention and in which- Patented Nov. 18, 1958l Fig. 1 is a View showing the hydraulic load lowering apparatus in elevation and partially in section;

Fig. 2 is a vertical section of the apparatus shown in Fig. 1 and taken along the line 2 2 of Fig. 1;

Fig. 3 is a plan view of the apparatus; and

Fig. 4 is a View illustrating the mode of operation of the apparatus in conjunction with a conventional' crane hook and load.

With reference to the drawing, two cylinders 6 integrally closed .at the bottomV and open at the top are mounted on each side of the apparatus as illustrated (Fig. 1). The cylinders 6 are. rigidly held in mutually spaced parallel relation to leachl other by a U-shaped cylinder connecting frame 8 incorporatinga centrally located lifting eye 10, the U-shaped cylinder frame 8 with. the parallel cylinders 6 forming an'H-shaped cylinder unit. Housed within each cylinder 6 is a piston 12 attached to piston rod 14 which projects throughan aperture 16 in the bottom of the cylinder 6. A piston connecte` ing frame 18 in the lshape of an inverted U with theA ends of the legs having outwardly projecting lugs 15 is' firmly attached to the projecting ends of the piston rods 14 and holds them in mutually spaced parallel relation to." each other. The center of the piston connecting frame'` has a reinforced portion 19 and an elongated vertical aperture 20 within the reinforced portion 19. A load supporting swivel hook 22 is independently carried in the aperture 20 so that its shank 24 is encompassed by the reinforced portion 19 of the .connecting frame 18, and

. the hookproper 22 extendsbelow the reinforced portion 19 of the frame 18. Attached to the top. of the shank 24 is a stop 26 which holds the hook in position and permits it to rotate freely in its mounting. /The axis 'of load support of the apparatus is determined by the line be;` tween lifting eye 10 and shank 24 of hook 22. i f

Removable sealing plugs 28 are threadedly connected to the t-op of each cylinder 6.` Packing glands 30 mounted in the bottom of each cylinder 6 encompass each piston rod 14. Positioned between the bottom of each cylinder 6 andits piston 12 are two helically coiled compression-` springs 32. compression, and they yieldably oppose the downward movement of the piston 12 under the force of a load. y An upper-port 34 and an intermediate port 36 are provided in the wall of each cylinder 6., The two upper ports are connected oy an upper conduit 38, and the two intermediate ports are interconnected by a lower conduit 40. Flexible hose lines 42 and 44 are respectively connected to upper conduit 38 .and lower conduit 40.

Both of the cylinders 6 are filled with hydraulic fluid 46 and the flexible hose lines 42 and 44 are connected through a hand operated needle valve 48.

In the operation of the material handling apparatus, the apparatus is attached t-o a crane or hoist hook 50 (Fig. 4) by its lifting eye 10, and a load 52, such as a heavy piece of machinery, is in turn attached to the swivel hook 22 of the apparatus either directly or by means of suitable intermediate tackle 54. The load 52 is moved near the desired location by the crane or `hoist and then lowered while the needle valve 48 is closed until it is a few inches above its final position. Precision control of the lowering operation is obtained independently of the crane or hoist brake by opening needle valve 48 the proper amount to effect .an accurate and deliberate setting of the load. When the needle valve 48 is opened by the operator, the hydraulic fluid 46, trapped in the cylinder 6 beneath the pistons 12, is released and permitted to flow through the intermediate ports 36. conduit 40, hose line 44, needle valve 48, hose line 42, conduit 3S, and upper ports 34, into cylinders 6 at a point above the pistons 12. The precisely controlled release of the Huid These springs 32 are tensioned to resist 46 permits the pistons 12 and piston rods 14 to move downward under the force of the load simultaneously and in equal amplitudes, and the piston connecting frame 18 and swivel hook .22 move responsively to the movement of the r-ods 14.

Conduits 38 and 40 permit the fluid 46 to flow freely from one cylinder 6 to the other on both sides of the pistons 12 at all times, and thus serve to equalize hydraulic pressures in the two 'cylinders 6. Within cylinders 6 the downward movement of the pistons 12 is yieldably opposed by return springs 32; thus, when the load 52 is released and needle valve 48 left open, springs 32 will force the pistons back to the top of cylinders 6 whereupon some of the fiuid 46 Will'be transferred from above the pistons 12 back to its original position below the pistons, in the reverse of the path of flow followed in lowering. Intermediate ports 36 are positioned at a suitable height on the cylinders 6 to prevent piston travel below a certain point, the permanently trapped fluid 46 stopping any further piston movement below the intermediate ports 36. The positions from which the operator may control movement of the apparatus are limited only by the length of the two flexible hose lines 42 and 44.

An advantageous feature of the present invention not obtainable with the use of a single hydraulic cylinder is the minimal loss of crane height made possible through the combination of the U-shaped cylinder connecting frame 8 and the inverted U-shaped piston connecting frame 18 with the two double acting hydraulic cylinders 6. A further desirable property of the instant invention is the independent suspension of the swivel hook 22 in the vertical aperture 20 of the piston connecting frame 18 which permits relatively friction free rotation of this load carrying hook about its shank 24 as an axis without the need for the costly machining or the undue increase in the length of the unit which is required to provide a freely rotatable hook when only one hydraulic cylinder is used.

Having thus described my invention, what I claim as new and wish to secure by Letters Patent is:

A hydraulic material handling apparatus comprising a first U-shaped web and a second U-shaped web placed back to back in a cornmon plane with proximate bight portions and oppositely extending legs, the ends of the legs of the rst U-shaped web defining the top of the apparatus, the ends of each leg of the second web having an outward projection, the first web having a hook receiving means centrally of its bight portion, the second web having a hook member attached to the bight portion between the legs thereof, said hook and said hook receiving means establishing an axis of load support through the' apparatus; said 'rstiweb supporting a pair of spaced, elongated hydraulic cylinders parallel to but spaced from said' axis of load and extending one along each leg of the U of said first web and beyond the bight portion of said first web to form an H-shaped unit, each cylinder containing a piston in the upper portion, an axial piston rod having one end. attached to the piston andthe other end extending through the lower end of the cylinder and being attached to said outward projection on one leg of said second webv anda coil compression spring around said rod biasing said piston` away from said lower end; a first conduit communicating between the upper ends of said cylinders, a second conduit communicating between the central portions of said cylinders, an elongated liexible conduit interconnecting `said first and second conduits and a control valve in said `elongated conduit whereby a load supported by saidhook, when the apparatus is supported by said hook receiving means and said pistons are in the upper portions of the cylinders, may be retained by hydraulicpressure in the cylinder by maintenance of said valve in a closed position and said load may be lowered byopening said valve to permit hydraulic fluid to fiow from below to above the pistons in said cylinders, said springs returning the pistons to their upper positions whensaid hookis not supporting a load and said valve is open.- l

References Cited in the le of this patent l UNITED STATES PATENTS 101,681 Towle Apr. 5, 1870 1,597,074 Keller Aug. 24, 1926 1,613,563 Grattan Ian. 4, 1927 2,500,459 Hoover et al. Mar. 14, 1950 2,734,463 Hursh et al. Oct. 5, 1950 

